System (ps/top) & bhyvectl memory usage differences

[Matt Churchyard]

Hello,

Is there a reason why the resident memory used by a bhyve guest is quite different when comparing ps/top & bhyvectl?
Does bhyvectl take in account something in kernel space that top/ps doesn't see?

USER   PID %CPU %MEM     VSZ    RSS TT  STAT STARTED      TIME COMMAND
root 12670  0.1  1.4 2120984 951764  1  SC+  22Jan20 157:29.22 bhyve: smtp-a (bhyve)

# bhyvectl --get-stats --vm=smtp-a | grep Res
Resident memory                                 1439875072

1.4G vs 925M

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Another thing I've just remembered, which is probably unrelated to the above but still concerning memory.
I have a guest with 2G memory allocated, and dmesg lists 2048MB real memory. The real & avail figures are also quite close which resembles the output I generally expect on real hardware.

Hypervisor: Origin = "bhyve bhyve "
real memory  = 2147483648 (2048 MB)
avail memory = 2043318272 (1948 MB)

However, I have a guest with 5G allocated, and get the following in dmesg -

Hypervisor: Origin = "bhyve bhyve "
real memory  = 6442450944 (6144 MB)
avail memory = 5141663744 (4903 MB)

bhyveload -m 5G ...
bhyve -c 2 -m 5G -AHP ...

I haven't tested where it seems to change. My only theory is that it could possibly be something to do with crossing the old 32bit limit?

Regards,
Matt Churchyard